1. Field of the Invention
The present invention relates to a vehicle window glass and a process for manufacturing the same, more particularly to a vehicle window glass having an infrared cut-off (shielding) function or the like and a process for manufacturing the same.
2. Description of the Related Art
There has been known in recent years imparting an infrared cut-off (shielding) function etc. to a glass by forming a thin film containing an expensive and rare metal, such as indium, on the surface of a glass plate (see International Publications WO2004/01338 and WO2005/095298, for example).
In the infrared shielding glass disclosed in International Publication WO2004/01338, ITO powder with an excellently heat-resistant fluorine component added thereto is used, whereby sol-gel processing is made practicable in the formation of an infrared cut-off film even at temperatures as high as 350° C. or more. The fluorine component contained in the ITO powder is introduced into the infrared cut-off film while thermally protecting the ITO fine particles.
In the infrared cut-off glass disclosed in International Publication WO2005/095298, an infrared cut-off film, made up of an organic-inorganic composite film where organic matter and an inorganic oxide are hybridized and ITO fine particles as an infrared cut-off component added to the composite film, is formed on at least one surface of a glass plate.
A conventional vehicle window glass is manufactured by using a glass plate having been cut to a predetermined shape and chamfering the edge portion of the glass plate. However, there has been known a vehicle window glass with a transparent film layer formed on its edge portion, thereby requiring no chamfering (see Japanese Laid-Open Patent Publication (Kokai) No. 2002-12024, for example).
However, in the infrared shielding glass described in International Publications WO2004/01338 and WO2005/095298, the infrared cut-off film formed on the surface of a glass plate is likely to peel off the glass plate. Particularly when such an infrared shielding glass is used for a vehicle window glass, as shown in FIG. 6, an edge portion 13a of the infrared cut-off film 13 formed on the surface of an infrared shielding glass 11 experiences a force whenever the infrared shielding glass 11 comes in contact with a glass run 12 in a door sash 14 of a vehicle, and besides, the infrared cut-off film 13 is thick. Thus, the infrared cut-off film 13 tends to peel off from its edge portion 13a. 
In the vehicle window glass described in Japanese Laid-Open Patent Publication (Kokai) No. 2002-12024, since its edge portion does not undergo chamfering, the edge portion has low strength and its surface is rough and appears poor. Besides, the transparent film layer on the edge portion of the glass plate is not integrally formed with the transparent film layer on the surface of the glass plate, and thus the transparent film layer formed on the surface of the glass plate is likely to peel off the glass plate.